Lunch box



FIG. 1 is a right side elevational view of a lunch box showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a left side elevational view thereof; and,

FIG. 5 is a front elevational view thereof. 

The ornamental design for a lunch box, as shown and described. 